The battery is one of the most important and most expensive parts of an electric or hybrid vehicle. For this reason, most original equipment manufacturers (OEM) require the suppliers of battery packs to provide a guarantee for their batteries. In addition to the OEM requirements, such guarantees are also demanded by the legislation for emission-free vehicles (zero emission vehicles, ZEV), for example. Normally, the period for which a guarantee is required is between five and ten years. A further important aspect is the cost. Battery packs cost several thousand euros, and if they are returned to the supplier by the OEM, then it is extremely expensive to replace a used battery with a new one.
Since this guarantee period and the costs for batteries are not comparable with those for other vehicle parts, it is important for the suppliers of the batteries to use special measures to ensure that the battery has not been handled (improperly) by an unauthorized person.
By way of example, improper handling can involve                incorrect charging/discharging of the battery and/or        replacement of a sound battery with a defective or old battery.        
Mishandling through incorrect charging/discharging can be identified on the basis of the prior art by using a battery data recorder that records the current supplied to the battery and drawn from the battery during charging and discharging and stores the charge state in a storage medium, such as an electrically erasable programmable read-only memory (EEPROM) or a flash EEPROM. These recordings can be evaluated at a later time outside the battery (off board) for analysis purposes or to check the validity of the guarantee claims.
A method for identifying a hand-held machine tool is known from the publication DE 10 2007 007 506 A1. To prove whether a damaged tool is an original part, this publication proposes that, in order to identify the hand-held machine tool, the housing of the hand-held machine tool be produced at least to some extent from a plastic that has an indicator component admixed with it.
No method is known to date for proving that a functional battery has been replaced with a defective or old one.